For a copper-tungsten microlayered composite material for electrical contact applications, which is prepared by electron-beam evaporation-condensation, the changes in its structure, conductivity, hardness, and mechanical properties in tension at room temperature and elevated temperatures are studied versus the tungsten content and heat treatment conditions. New morphological features of the condensed composite and the related changes in the material properties have been revealed. The conditions for the formation of structural defects and their influence on mechanical properties and fracture behavior of the material in tensile tests have been investigated. A relationship has been established between the tungsten content of the composite, its structure, strength, and hardness.

In order to evaluate the maximum size of the flaky inclusions in a Si-added noncombustible Mg casting alloy, we propose a method for evaluation of distribution characteristics of flaky inclusions. The validity of this method is verified through simulations with arbitrary inclusion distributions. The proposed method enables prediction of the maximum size of the flaky inclusions in an arbitrary volume of material.

Titanium carbide- or carbonitride-base tungsten-free hard alloys with a nickel-molybdenum binder, which can effectively replace tungsten alloys in metal and alloy cutting, are examined. The proper choice of the composition and grain sizes of the carbonitride component allows the bending strength of 1500 MPa and hardness of 90―91 HRA to be reached. High-temperature hardness and fracture toughness are of the same order as those of hard tungsten alloys.

The paper addresses damage accumulation processes that occur during static deformation in steels 45 and 09G2S and in brass L63 in the initial state and upon grain annealing. The authors discuss new experimental evidence on the damage accumulation kinetics during deformation of polycrystalline materials that differ in nature and grain size, including materials in the unloaded state and those under stresses, with small and very small strains (0.05―0.15%). The results obtained have been the necessary physically consistent explanations. Analytical approximations of the correlation between the main mechanical properties of materials (hardness, yield stress, and ultimate strength) and their structure parameters (grain size) are given.

Based on generalizing the results of numerous experimental investigations, the empirical relationships between the fatigue limit of steels and the stress gradient are proposed and justified, which take into account the fatigue damage behavior of smooth specimens and specimens with stress concentrators. A method for determining the parameters of these relationships with consideration of the mechanical properties of steels is proposed. Good agreement of the proposed relationships with the experimental results is shown.

The test data for ring specimens from heat exchanger tubes without defects are compared to those for specimens with various types of defects. A relation between strength characteristics of the specimens and the nature and depth of defects has been clarified.

A nonlinear model of the process of low-temperature discontinuous yielding of metals has been constructed, which allows the totality of strain jumps to be described as a function of the mechanical properties of material and dynamic characteristics of the loading system. The adequacy of the model has been experimentally verified for austenitic steel and an aluminum alloy.

The fatigue test results and the mechanical characteristics in static tension are obtained for specimens of titanium alloys belonging to the known classes of materials with a reference globular or bimodal microstructure and the so-called fine-grained β-transformed microstructure provided by the rapid heat treatment technique. The microstructure of the materials under study is analyzed. The microstructural parameters responsible for the fatigue strength of particular material have been found. The comparison is made between the fatigue limits obtained experimentally and calculated using the models previously developed by one of the authors.

The microhardness of the initial specimens of SAV-1 avials was experimentally investigated. Modification of this mechanical characteristic as a result of alloy irradiation in the channels of a research nuclear reactor WWR-SM was studied. The nonlinear pattern of material hardening after irradiation at low fluence rates (1015 ― 1018 neutron/cm2) was revealed. The radiation effect of avial microhardness variations is established to be a certain function of irradiation doses and indentation loads. The possible reasons of an increase in hardness of irradiated specimens are discussed. The radiation-induced hardening of aluminum alloys is assumed to be determined by generation of point flaws and dislocations, blocked by defects and interstitial phase decay products.

The paper addresses the dependence of acoustic emission produced in rolled hafnium GFÉ-1 under tensile deformation on the material's structural state. A correlation has been established between the material structure, the level of mechanical properties and the values of acoustic parameters. Acoustic emission in non-recrystallized hafnium under tensile deformation is recorded only at the stages that precede fracture. Upon recrystallization annealing at temperatures of 1123 and 1373 K acoustic emission occurs at all the stages of tensile deformation. The highest level of acoustic emission activity in hafnium is observed during the transition from elastic to elastic-plastic strain.

We present a method for refining the parameters of the model for nonlocalized damage accumulation in the steel 20 under static deformation, which are determined by variation in elastic modulus and degree of homogeneity of the material, that corresponds to the scatter of hardness characteristics during mass measurements at different stages of repeated static loading.

We investigate the structure, hardness, strength, plasticity and fracture character of Cu-Cr microlayer composite material for electric contacts with prescribed microlayered structure and chemical composition in the temperature range from 290 to 1070 K. The correlation relationships between the hardness and strength characteristics have been established.

The analysis of the mechanical state of the materials of a new rail and a rail after long-term operation are performed on the basis of the obtained data on the distributions of hardness over the cross sections of rails and the spread of the characteristics of hardness.

We present experimental data on the low-temperature deformation behavior of some alloy structural steels under plane stress conditions simulating the material operation in pipe and shell structures. The experimental part of the investigations involves loading of thin-walled shell specimens with an axial force (tension, compression) and internal pressure, including tests at low temperatures.

We present the results of investigations into the influence of high-density electric current pulses on the mechanical characteristics of rail steels in the initial state and after a long in-service operating time. The effect of in-service loading conditions and modes of exposure to electric current pulses on the steel mechanical properties and their anisotropy is shown.

We discuss the methods of assessment of stress-strain state and stress gradient in nonuniformly stressed structural components under elastic and elastic-plastic cyclic deformation. We systematize the research findings on fatigue of metals and alloys, including the stress concentration case, as well as the methods that describe the dependence of fatigue characteristics on the stress gradient.

The use of a phase-mechanical approach to the analytical estimation of the efficiency of steels in hydrogen and hydrogen-containing aggressive media is proposed. Using literature data, the behavior of 50 steels has been generalized, and significant correlation relations between the static properties of steels in the air, their chemical composition and characteristics of static, high-and low-cycle fatigue in media have been obtained. The discrepancy between actual and calculated data does not exceed 8―18%.

Within a single methodological approach, we establish correlations between the ultimate and fatigue strengths in tension and bending for 48 types of steel of various structural classes subjected to various procedures of thermal treatment. The ratios of the mean and mean-square differences between the actual values and the values computed according to the most efficient known relation and according to the proposed relation are equal to 2 and 2.5, respectively.

A procedure for the prediction of the load-carrying ability of unidirectional-fiber reinforced composite laminates is presented, which is based on a structural-phenomenological model developed of the degradation of layer elastic constants during deformation and takes into account the presence of heat stresses and temperature dependences of the thermomechanical characteristics of layer. The efficiency of the procedure has been confirmed by the results of tests of carbon laminates with different reinforcement schemes both at room temperature and at cryogenic temperature.

Mechanical properties of WWER-440 RPV weld joints have been studied with account of different states of the material: baseline (unirradiated), irradiated up to the average fast neutron fluence of 6.5.1019 n/cm2, irradiated and eventually annealed, re-irradiated with the accumulated fast neutron fluence 1.3.1020 n/cm2. Tensile, impact fracture, and fracture toughness tests were performed for each state of the material with the use of Charpy specimens (standard, reconstituted, and pre-cracked).